Meningococcal vaccine
The meningococcal bacterium causes inflammation and pus in the brain. Illness includes a very rapid onset of fever headache, stiff neck, and coma. Infection occurs via airborne droplets from carriers who have no symptoms. Risk is highest from December through June in certain areas of sub-Saharan Africa and in close living quarters, such as dormitories. Traveling adults receive a single dose of vaccine. A booster dose is given 3-5 years later, if at new or continued risk. A painful swelling from shoulder to elbow can occur following vaccination; other severe side effects are rare.